Micaceous Haematite

A variety of haematite occurring as minute, splendent, greyish-purple flakes like mica, known to the miners who worked it as 'shiny ore'. It was not smelted for iron but ground and used as a pigment: its flat, overlapping flakes lie down in a paint film and armour it against water and rust, which made it the basis of protective coatings for ships and steel bridges.